[Letux-kernel] USB3-port on OMAP5432EVM

Roger Quadros rogerq at ti.com
Fri Feb 17 09:39:50 CET 2017


On 17/02/17 02:02, Chanwoo Choi wrote:
> Hi Roger,
> 
> On 2017년 02월 16일 22:43, Roger Quadros wrote:
>> +Chanwoo
>>
>> On 15/02/17 23:36, Tony Lindgren wrote:
>>> * Tony Lindgren <tony at atomide.com> [170215 13:01]:
>>>> * Roger Quadros <rogerq at ti.com> [170214 01:44]:
>>>>> You can enable dwc3 trace events.
>>>>>
>>>>> cd /sys/kernel/debug/tracing
>>>>> echo 1 > events/dwc3/enable
>>>>> echo 0 > events/dwc3/dwc3_readl/enable
>>>>> echo 0 > events/dwc3/dwc3_writel/enable
>>>>> echo 1 > free_buffer
>>>>> echo 2048 > buffer_size_kb
>>>> For me the issue was I had to change my sysfs scripts to start doing
>>>> echo -n instead of just echo. Things are working for me now with Linux
>>>> next.
>>> Then in host mode after connecting a device, I see the following warnings
>>> with Linux next and lockdep enabled if host mode is forced with
>>> dr_mode = "host":
>>>
>>> CONFIG_DEBUG_LOCKDEP=y
>>> CONFIG_DEBUG_ATOMIC_SLEEP=y
>> Looks like extcon is calling the notifiers while atomic. (spinlocks held, IRQs disabled?)
>> Does this needs to be fixed at extcon layer or dwc3-omap should
>> execute the mailbox in a workqueue?
> 
> Right, Now extcon layer is working withing the spinlock range
> because of reducing the latency to notifier the status of external connector.
> I recommend that dwc3-opap better to use the workqueue.

OK Chanwoo. Thanks.

-- 
cheers,
-roger


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